The present invention relates to a looper thread guiding mechanism, and more particularly, to such mechanism in which a looper thread passing through a thread hole formed at a tip end of a looper is guided to a base portion thereof in a sewing machine such as an overlock sewing machine.
In a sewing machine such as an overlock sewing machine, a looper is provided in a bed. The looper has a tip end portion formed with a looper thread hole and a base end portion provided with a thread hook or thread holding portion. Sewing operation is achievable by engaging the looper thread with the thread hook while the looper thread is passed through the thread hole. The thread hook is distant from the thread hole, and a great number of mechanical components are densely arranged around the looper. Therefore, the act of engaging the looper thread with the thread hook may extremely troublesome if the thread hook is stationarily provided.
To facilitate the looper thread engagement work, Japanese Utility Model Publication (Kokoku) No.3-6292 proposes an arm member pivotally supported to a looper arm. The arm member has a thread hook portion at its tip end, so that the looper thread engagement work is performed during displacement of the thread hook portion in the pivotal motion of the arm member.
However, according to the above proposed arrangement, a space is required around the looper for allowing the arm member to be pivotally movable. To this effect, it is necessary to overcome a spatial problem in that the positions of other components around the looper must be altered to obtain the sufficient space. Further, since great number of mechanical components are disposed around the looper, operability of the arm member may be degraded, and as a result, it would be rather difficult to fully simplify the looper thread setting work.
Particularly, in the case of the overlock sewing machine whose bed densely houses therein an overlooper, an underlooper and a double loop looper along with other components. it would be almost impossible to provide the looper thread guiding mechanism with respect to each one of the loopers due to the spatial problems.